1. Field
Example embodiments relate to substrates suitable for embodying optical devices, electronic devices, and micro-electromechanical systems (MEMS) structure together and methods of fabricating the same.
2. Description of the Related Art
Semiconductor integrated circuits employ electronic communication to electronically transmit and receive data. Semiconductor integrated circuits are integrated on a printed circuit board (PCB) and electronically communicate with each other via wires. There are limits in reducing the electrical resistances between semiconductor integrated circuits. Furthermore, electronic communication may be affected by external electronic waves. Due to such reasons, increasing the communication speed between semiconductor integrated circuits may be difficult.
Recently, optical interconnection or optical communication is employed to increase the communication speed between semiconductor integrated circuits. Optical communication includes transmission and/or reception of optical signals including data. Compared to electronic communication, optical communication may result in less interference by external electronic waves and enables faster communication.
For optical communication between semiconductor integrated circuits, embodying an optical device in a semiconductor integrated circuit may be necessary. Furthermore, a region for arranging optical fibers for optical communication and a micro-electromechanical systems (MEMS) region for forming an MEMS structure may be required.
To embody an optical device and an electronic device together on the same substrate, a silicon on insulator (SOI) substrate may be employed. An SOI substrate includes a buried oxide layer on a substrate and an epitaxial layer thereon. The buried oxide layer is located at a predetermined or given depth from a surface of the SOI substrate and has a predetermined or given thickness.
However, the thicknesses of an epitaxial layer and a buried oxide layer suitable for an optical device differ from those suitable for an electronic device, and a region requiring an MEM structure may be a region without a buried oxide layer.